Question

Show transcribed image textMost circuits in your computer are "logic circuit". This type of circuits uses voltage level to represent logic level 'high' (i.e. "1") or logic level 'low' (i.e. "0"). A certain type of logic circuit (TTL) considers voltage below 0.7v as a "low" and voltage above 2v as a "high". In the following circuit, the block on the left represents the output circuit a TTL logic circuit. When the switch is in the 'up' position, the chip output a "high" (with a 0.4mA current source connected to the output pin). The circuit shown on the right is a model of the input of such a circuit. In a typical logic circuit, one output is connected to more than one input (as shown in the diagram below). How many inputs can an output drive while guarantees that the voltage Vin is in the range of high (>2v) and low (<0.7v) (both conditions must be true) ? (Hint: If there are, say, five inputs connected to a single output, there are essentially five 2.5k resistors connected in parallel and same for the 50k resistors) The output circuit is only an equivalent circuit. According to this circuit, the output voltage can become very high. for example, when only 1 input chip is connected, the high voltage is. 0.4mA*50k=20v. The actual circus's output voltage however is limited by the supply voltage 5v. Similarly, the low output voltage will not go below 0v.